1. Technical Field
Embodiments of the invention relate to thermal sensors. More particularly, embodiments of the invention relate to design, manufacture and use of Micro Electro Mechanical (MEMS) thermal sensors in an interconnect layer of an integrated circuit.
2. Background Art
Thermal sensing on integrated circuits has previously relied upon nano-meter size, transistor based thermal sensors which operate according to a voltage reference. For example, current thermal sensors in processor cores include a bipolar transistor using a bandgap reference to detect temperature, where the voltage across a junction will change with temperature.
However, these thermal sensor techniques rely upon analog transistors which, due to their size, are very sensitive to manufacturing process variations. Such sensitivity impacts the sensor accuracy and linearity. Thermal sensor accuracy and linearity are critical to operations of a processor core, for example, since they can lead to power loss platform noise, reliability degradation and platform performance loss.
Due to continuing process scaling, process variations have an increasingly severe affect on the accuracy of thermal sensing transistors which rely upon a bandgap voltage reference. In addition, a critical thermal limit for operation of an integrated circuit is often in the interconnect layer and not in the transistor layer.